New evidence for the Qinghai-Xizang (Tibet) Plateau as a pilot region of climatic fluctuation in China

Over 40 a observed temperature data in 172 stations in China and historical proxy data were analyzed. Evidence suggested that during 1980–1994, the warmest year appeared first in southeastern part of the Qinghai-Xizang (Tibet) Plateau (henceforth SETP) and then gradually spread northwards and eastwards to eastern China. The climatic change on century time scale in recent 600 a shows 3 relatively warm and clod stages in China. Each warm and cold stage appeared first in Tibet Plateau (henceforth TP) and then in the Qilian Mountains, then in the eastern parts of China. The warm and cold stages in TP were 10–60 a earlier than in the eastern China. The facts show that TP is a pilot region of climatic fluctuation in China on the time scale shorter than 10³a.     

Buckling of a ferromagnetic thin plate in a transverse static magnetic field

An energy theory is proposed on the buckling of a ferromagnetic thin plate in a transverse static magnetic field. The analytic solution of critical field for plates is obtained by using variational method. It is shown that the critical magnetic field is not only influenced by the ratio of the thickness to the length, but also by the width, total length and the magnetic susceptibility of the specimen. Theoretical calculations agree with experiments reasonably.     

Calculation method of electronic structure and its application to (I h andI) fullerenes

A new calculation method was discussed to treat the Hückel Hamiltonian of any fullerene with a certain point group symmetry. This method was applied to calculating the electronic energy levels of icosahedral fullerenes C\-n(I\-h: n=60h 2, 0相似文献   

支持CAD／CAPP／CAM集成和并行的制造特征

由于设计和制造过程的复杂性,目前还没有一种有效的方法能彻底解决产品设计、制造和生产管理等生命周期内各个阶段的信息集成问题．探讨了并行工程下的ＣＡＤ／ＣＡＰＰ／ＣＡＭ的集成框架,提出了支持ＣＡＤ／ＣＡＰＰ／ＣＡＭ集成和并行运行的制造特征,并在商品化ＣＡＤ／ＣＡＭ软件ＵＧⅡ上进行了开发工作．该系统已通过纺织行业箱体、柴油机行业的油泵以及机床厂的主轴箱等多种零件考核．     

基于任务的产品工艺设计过程管理

在分析产品工艺设计流程现状的基础上,研究了现有ＣＡＰＰ系统中工艺过程设计和过程管理,提出了任务驱动型的ＣＡＰＰ思想．认为工艺设计的过程本质上是对任务完成过程的集合,通过对任务的生成、监控、设计、提交、签审、发放,正好控制工艺设计的流程,并在ＣＡＰＰ系统开发中进行了成功的尝试,为工艺设计的管理提供了一种可行的方法．     

吸收比-系数倍率法及其应用——水杨酸钠、安替比林和咖啡因的同时测定

用吸收比－系数倍率法同时测定撒痛风注射液中水杨酸钠、安替比林和咖啡因三组分的含量。它们的回收率分别为１００．７％～１０２．１％、９５．９３％～１０４．５％和９７．５７％～１０１．７％。     

On analytical treatment of all boundary and volume integrals in BEM

In this paper, the integrals appeared in BEM model for Poisson equation are all implemented analytically. Wherein, the boundary and the domain are discretized by linear boundary elements and linear internal triangle cells respectively. The closed formulations for all integrals are presented so that the computer effort for numerical solution is reduced considerably with higher accuray. The numerical example shows that the results are more accurate in comparision with Gaussian integration in the same discrezition. The basic idea of this paper could be extended to BEM model for Helmholtz equation and/or the time-dependent second other differential equations. Supported by the National Natural Science Foundation of China Tang Shaowu: born in 1971, Ph. D.     

关于二维Navier—Stokes方程的不稳定性

应用分层理论证明了二维Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的ｃ＾２不稳定性,并给出了重要例证分析。     

人性与人性平衡初探

人性是由生存欲、占有欲、性爱、情爱、责任心、义务感、同情心、怜悯心、惰性等多种要素组成的。人性诸要素之间的关系是互相平衡与互相制约的。这种平衡与制约遵循着四大规律：第一,人性要素的不可缺失性;第二,人性总体和总趋势平衡;第三,人性某个或某些要素扩张有一个“度”;第四,人性平衡是由简单到复杂、由低级到高级、由个别到普遍的发展过程。     

双曲型叶片的数控加工模型研究

给出双曲型点构成的叶片工作面的解析方程,并用主曲率方法给出了刀具参数、数控加工中的步长和行距的定量计算模型,最后用等螺距叶片工作面算例验证本文所供方法不但确保了叶片工作面造型精度,而且大大地提高了加工效率．